Resonance and Relaxational Dispersions around the Domain Freezing Temperature in KH_2PO_4

概要

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The resonance and the relaxational dielectric dispersions of KH2PO4 found in the ferroelectric phase were examined for ordinary and lossy specimens. The magnitudes of these two dispersions decreased markedly with crystal defects as well as with a d.c. bias field. A universal relation between the free dielectric constant $\varepsilon^{X}$ and the elastic stiffness $C_{66}^{E}$ was found regardless of the specimens and their states examined. The small $C_{66}^{E}$ and the large $\varepsilon^{X}$ were obtained for the specimens with high densities of domain walls. The mean value and the standard deviation of the energy parameter $E$ in the relaxation time, $\tau{=}\tau_{0}\ \exp\ \{E/(T-T_{0})\}$, as well as the Vogel-Fulcher temperature $T_{0}$ decreased with the crystal defects. A possible model for the domain freezing is proposed in connection with these two dispersions.
社団法人日本物理学会の論文
1988-06-15